fh451v kawie motor has no power..

Discussion in 'Mechanic and Repair' started by nxfirebird, Aug 15, 2011.

  1. nxfirebird

    nxfirebird LawnSite Member
    Messages: 3

    i've got a bobcat walk behind with the fh451v, after letting it warm up i went to throttle it up, the motor back fired and changed pitch. now it has no power as in it barely pulls the blades. it starts and runs but is super rich, and fouls plugs. i've been all though the carb, changed the gas out, it seems to be getting gas, and has new coils. i've even pulled the muffler off and checked to make sure each pulley turns freely.
    it almost seems to be out of time, but i don't know how that could have happened instantly.

    i'm at a real loss, any ideas?

    thanks john.
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,248

    How recently have the valves been adjusted? I believe Kaw recommends every 300 hours.

    If it seems to be running rich, it's possible you have had a valve hang up on you and you could be running on one cylinder--that you will be able to determine if you adjust the valves. If in doubt a compression or leakdown test will aid in diagnosis.

    With out proper tools, you could remove both plugs and hold a finger over each spark plug port. With adeqate compression, it should push you finger off the port as you crank the engine. Keep the spark plug wires away from your hand unless you enjoy a shock.
  3. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    If you perform the valve adjustment check as Dutch mentioned and find one way out of adjustment, I would suspect a piece of carbon broke loose from the backfire and got stuck under the valve seat area....


    Yeah, I see ya up there Dutch..... http://www.**********.com/forums/images/smilies/1223.gif
    Last edited: Aug 15, 2011
  4. nxfirebird

    nxfirebird LawnSite Member
    Messages: 3

    now that wasn't something i had thought of yet. i bet they haven't ever been touched. i just bought this mower a couple of week ago. it mowed 10 yards and do this. very frustrating, but i will crack the valve covers and see if i got something going on in there.

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